Medico-technical measuring device and measuring method

ABSTRACT

A medico-technical measuring device for measuring a property of a fluid, such as pressure for pressure measurement, includes a line extending along a central longitudinal axis to guide a fluid, such as blood, within a longitudinal cavity delimited by a wall. A sensor unit has a sensor and measures a property of the fluid guided in the longitudinal cavity. The line is provided with a radial cavity inserted in the wall in a radial direction, in which the sensor unit is at least partially arranged, and which is integrated in the wall such that the sensor is in communication with the fluid. In this way, a measuring device can be provided that allows simple handling—in particular, in combination with a comparatively precise measurement—especially, pressure measurement. The measuring device may be produced according to a method and the measuring device may be used in a measuring method.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. Ser. No. 15/301,143, filedSep. 30, 2016 which is the U.S. national phase of internationalapplication No. PCT/EP2015/001001, filed May 15, 2015, which claimspriority to European application No. EP 14001728.6, filed May 15, 2014,each of which are incorporated herein in their entirety.

FIELD OF THE INVENTION

The present invention relates to a medico-technical measuring device formeasuring a property of a fluid—in particular, for pressuremeasurement—comprising a line extending along a central longitudinalaxis and configured to guide a fluid—in particular, blood—within alongitudinal cavity delimited by a wall, and a sensor unit having asensor, which sensor unit is configured to measure a property of thefluid guided in the longitudinal cavity.

The present invention further relates to a method for producing themedico-technical measuring device, comprising the steps of providing aline with a wall and arranging a sensor in the line. The presentinvention relates to a medico-technical measuring device with individualcharacteristics as disclosed herein, as well as a production method or ameasurement method each with individual characteristics as disclosedherein.

BACKGROUND OF THE INVENTION

Measuring devices and sensors are known which are arranged on aconnector, adapter, or spacer between individual sections of a line. Theline guides a fluid—in particular, an isotonic saline solution or othercrystalloid infusion solutions or blood—the property of which—inparticular, pressure—is to be recorded. In such measuring devices, thereis often the risk of coagulation (or so-called blood clotting) orhemolysis—in particular, as a result of edges, undercuts, or fluidicallyunfavorable transitions. The connecting elements or connectors alsoincrease the risk of leakages—in particular, on interfaces between aconnector and an extra-corporeal hose kit or in the measuring system—andmust be additionally checked. In particular, the problem is known frompractice that leakages can occur, e.g., on Luer connections. Especiallyin the case of extra-corporeal circulation, there is then the risk thatair can potentially be sucked into a discharge line, in which there canbe a low pressure, and mixed with the fluid/blood. From a feed line inwhich there can be an overpressure, there is the potential forfluid/blood to be squeezed out of the line. In this case, the sterilityof the overall device can no longer be ensured. In addition, theconnector or adapter must be mounted on the line, and a seal, bondedjoint, or other interface, which is as sterile as possible or which canbe sterilized, must be able to be ensured.

As an alternative to such measuring devices or sensors coupled orintegrated in the line, a measurement—in particular, a pressuremeasurement—can also be effected outside the line. The correspondingsensor can then directly record a pressure, e.g., by means of a watercolumn. However, a so-called priming operation is required for this typeof pressure measurement, in order to be able to start the pressuremeasurement. With priming, the hose system is filled with a crystalloidsolution, such as isotonic saline solution (NaCl), after which the hosesystem is vented. There is a risk that the venting of the line/hosesystem will be carried out incorrectly. During the measurement, there isa risk that fluid/blood penetrating the crystalloid solution in a lineleading to a measuring sensor might impair or interrupt the measuringprocess, which can be life threatening.

Also disadvantageous in this type of pressure measurement are measuringerrors, which are caused by gas inclusions in the water column. Also, inmost cases, the pressure measurement itself can be performed only with adelay, since a pressure wave must first be transferred through thewater. Therefore, such a direct pressure measurement makes it difficult,for example, to synchronize a pump with the arterial pressure curve ofthe patient.

The German patent application (Offenlegungsschrift) DE 10 2005 063 410A1 describes a blood vessel catheter in which a blood pressure sensor isarranged on a housing which is coupled to a catheter tube.

The German patent application (Offenlegungsschrift) DE 10 2007 038 402A1 describes a device for recording a pressure in which a sensor elementis embedded in the wall structure of a line separate from a mediumguided along the line.

The European patent specification EP 0 328 558 B1 describes an elastichose on whose internal surface a coating is applied in which a pressuresignal can be measured when the hose is deformed.

SUMMARY OF THE INVENTION

An aim of the present invention is to provide a medico-technicalmeasuring device—in particular, a blood pressure measuring device—whichfacilitates easy handling—in particular, in conjunction with acomparatively exact measurement. The aim can also be described such thatthe medico-technical measuring device should have a simple constructionand/or be able to minimize the risk of impurities or air inclusions orleakages.

The aim is accomplished by means of a medico-technical measuring devicefor measuring a property of a fluid—in particular, for pressuremeasurement—comprising

-   -   a line—in particular, a hose line—which extends along a central        longitudinal axis and is configured to guide a fluid—in        particular, blood—within a—in particular,        cylindrical—longitudinal cavity delimited by a wall, and    -   a sensor unit having a sensor—in particular, a pressure        sensor—which sensor unit is configured to measure a property of        the fluid guided in the longitudinal cavity, wherein, with the        measuring device according to the invention, it is provided for        the line to have a radial cavity inserted in the wall in a        radial direction, in which cavity the sensor unit is at least        partially arranged and which is integrated in the wall such that        the sensor is in communication with the fluid in the        longitudinal cavity.

The arrangement of the sensor directly in the wall has metrological oralso constructive advantages. The sensor can be easily arranged on ametrologically preferable position—in particular, in close proximity toa flow path of the fluid, or even directly in the flow path. Inparticular, the number of interfaces can also be reduced—especially, tojust a single interface in the wall. The arrangement of the sensorsintegrated into the wall renders spacers, couplings, or otherconnections superfluous. For example, no Luer connections or otheraccess points to the line are required. As a result of this, the risk ofleaks or of any non-sterile interfaces is considerably reduced. However,with the spacers or adapters—in particular, Luer connections—mostcommonly used in prior art, there are always at least two or threeinterfaces—namely, the interface(s) between the spacer or adapter andthe line on the one hand, and the interface between the spacer oradapter and the sensor on the other. Therefore, it is important toemphasize that a line within the meaning of the invention is, inparticular, not a spacer, a connector, or an adapter. In addition,incorrect operation of any connections can be also be avoided. It can,for instance, be avoided that, for example, in an extra-corporeal linesystem or hose system (such as those used in dialysis, in heart or lungsupport, or with a cardiopulmonary bypass in cardiac surgery, or in acatheter or a sheath, e.g., in cardiology) in a section with negativepressure (in particular, with a pressure less than atmosphericpressure), air be drawn into the line/hose system or the catheter in thearea of the pressure measurement arrangement, or that fluid/blood escapefrom the circulation in a section with positive pressure (in particular,at the point where fluid/blood is fed back into the body).

A priming process, especially in relation to the sensor, is thereby nolonger necessary, which can save time and make the pressure measurementin certain (e.g., life-threatening) situations particularly useful.There are no longer any additional supply lines or hoses to be vented.In other words, the integrated arrangement of the sensors permits an“inline” measurement, without a time lag. The line/hose system(including a potentially provided catheter or cannula) guiding the bloodcan thereby be filled and vented independently of a pressuremeasurement.

In the last few years, sensors—in particular, pressure sensors—with eversmaller dimensions have become available. This now allows for anadvantageous arrangement of the sensor in direct proximity to the fluidto be measured. The integrated sensor can be arranged directly in thefluid stream, without influencing the fluid stream. This alsofacilitates a particularly exact (pressure) measurement. In thisconnection, an integration, for example, can also be effected in a wallwhich has a wall thickness in the range of only 1 mm to 3 mm.

Such an arrangement of the sensor also facilitates a largely arbitraryselection of the position of the sensor on any section or anycircumferential position along the line—in particular, a hose line. Thesensor unit or the sensor can thereby form a part of the wall.

A measuring device (in particular, a pressure measuring device) therebypreferably means a device which can guide, or feed or discharge, aspecific fluid in a specific state—in particular, in a flow state—andcan record and, optionally, at least partially evaluate at least oneproperty—in particular, the pressure of the liquid. The measuring devicecan preferably record and evaluate at least the pressure and,optionally, other physical or chemical variables as well. Such ameasuring device can, for example, be used for an invasive pressuremeasurement or in conjunction with an extra-corporeal circulation, e.g.,for renal replacement, cardiopulmonary support, or liver support. Theadvantages of good tightness and/or sterility can thereby ensue,especially with an invasive/implanted arrangement. By means of themeasuring device, the vital functions, for example, of a patient can bemonitored, e.g., heart muscle contractions (hemodynamics), or a loss ofpressure caused by extra-corporeal circulation can be measured.

The measuring device can thereby comprise several different sensors. Inaddition to the sensor, the measuring device can have additionalcomponents, such as a protective cap, a female connector (for example, afour-pole female connector) or a preferably water-repellent membrane,wherein the membrane can ensure a protection of the sensor againstexternal influences. The sensor can, for example, work on the basis ofthe differential pressure principle. The measuring device thenpreferably has a connection to the outside air or environment. Themembrane can be attached to a sensor cover over the sensor and protectthe sensor—in particular, the bonded electronic connections of thesensor. The membrane can prevent media (e.g., blood, water, isopropanol)from coming into contact with these sensor connections. The membrane ispreferably hydrophobic on both sides, i.e., in both directions, whereinair can be allowed to pass through (preferably) unimpeded.

One property—in particular, a pressure—can thereby also be measured inseveral measurement positions, depending upon the medical application—inparticular, a suction pressure in a first position upstream of a pump, apump pressure in a second position downstream of the pump, and anadditional one—especially, a reperfusion pressure—in a third positiondownstream of a membrane ventilator. In other words, the measuringdevice can optionally have a plurality of sensor units, or at least aplurality of sensors. Accordingly, the line (including any catheter orcannula present) can also have a plurality of radial radial cavities.

A fluid thereby preferably means a liquid; however, the fluid can alsobe a gas, or at least have gaseous components.

By line is thereby preferably meant any type of line which can be usedin conjunction with medical care, diagnosis, or therapy, e.g., also inconjunction with any catheters. The line can be part of a medicalinstrument or set of instruments. The—in particular—blood-guiding linecan be part of a so-called hose set or can form this hose set. The(hose) line can thereby also comprise a cannula, ensuring access to thebody, or be designed in sections as a cannula. The line is preferablyflexible, i.e., elastically pliable. In particular, the line can becurved or bent. The elasticity of the line is thereby not—or notnoticeably—influenced by the sensor unit. To a great extent, thediameter of the line can be freely selected. In particular, internaldiameters of, for example, 9.52 mm (⅜″) or 6.35 mm (¼″) are appropriate.

The wall, or even the entire line, can be designed from a flexibleplastic material—in particular, from polyvinyl chloride (PVC) material.In the simplest case, the line is, for example, a PVC hose frequentlyused in medical technology. The plastic material is preferably ahigh-purity, non-phthalate soft PVC. Thereby, a wall thickness of thewall and/or line is, for example, in the range of 1 mm to 5mm—preferably in the range of 1.2 mm to 3.5 mm, more preferably in therange of 1.5 mm to 3 mm, and particularly in the range of 1.6 mm to 2.4mm.

A sensor unit thereby preferably means a component of the measuringdevice by means of which a measuring signal—in particular, a pressuresignal—can be recorded and either processed or at least transmitted.

A sensor (in particular, pressure sensor) thereby preferably means acomponent of the measuring device by means of which a property of afluid can at least be recorded by a measuring signal—in particular, apressure signal. A property or a state of the fluid can thereby berecorded—for example, through a physical or chemical variable. Aproperty can, for example, be described by a specific portion of agaseous component, for example, a portion by volume of CO2 or O2. In sodoing, the sensor can, for example, be configured to measure theinfusion pressure or injection pressure in fluid-guiding medicaldevices. For example, a piezo-resistive sensor can be used.Alternatively, sensors can also be used which are based upon one or moreof the following physical principles or operating modes: for example,piezoelectric, capacitive, inductive, frequency-dependent, or sensorswith Hall element, fiber optic sensor. The sensor can thereby beinserted into the inner lumen of the line on its surface facing theblood, such that a continuous and smooth transition between the sensorand the inner lumen is ensured—in particular, to prevent coagulation orhemolysis in the area of the sensor.

A radial cavity thereby preferably means a recess introduced or providedin a radial direction, a bore, a cavity, or a hollowed-out area orsection, or take-up volume. The radial cavity can also be formed by alongitudinal cavity extending in a radial direction, which is onlyaccessible from one side of the wall. The radial cavity need notnecessarily be a duct or a hole in the wall.

An opening preferably means an aperture or a radial cavity whichcompletely breaks through the wall, i.e., is provided continuouslythrough the wall.

A recess preferably means a cavity extending in a radial direction froman inner side of the wall, i.e., an inner sleeve surface, which need notnecessarily run up to an external sleeve surface of the wall. In otherwords, the recess is not necessarily a hole in the wall, but can hollowout the wall—also just in sections—in a radial direction.

An arrangement “in communication with” thereby preferably means anarrangement in which the sensor is in direct contact with the fluid. Thesensor can be arranged in the fluid stream or on the side of the fluidstream or on the side of a flow path of the fluid stream.

According to an embodiment example, the measuring device is configuredto link the sensor unit in an individual (in particular, geometric)interface with the line—in particular, to attach/fix it directly to anexternal sleeve surface of the wall, thereby positioning it. As aresult, the risk of leakages can be reduced—in particular, in comparisonwith adapters or spacers which have several interfaces. In other words,the measuring device need have only one single interface or one singleattachment point or access point via which the sensor can be integratedin the line.

The sensor unit can be integrated in the line on the single interfacebetween the sensor unit and the line. The interface is therebypreferably formed solely by the radial cavity or by the radial cavityand an external sleeve surface of the wall.

An interface thereby preferably means a surface on which the sensor unitcan be connected to the wall. The interface can thereby also comprisedifferent surfaces, which are, however, preferably arranged in the samearea of the wall—in particular, adjacent to one another.

According to one embodiment example, the sensor is arranged in a radialposition between an/the external sleeve surface and an internal sleevesurface of the wall inside the wall distanced from the external sleevesurface—in particular, in a section which is arranged closer to theinternal sleeve surface than to the external sleeve surface. As aresult, the sensor can be arranged close to the flow path of the fluid,or even in the flow path, which facilitates a comparatively precise“inline” measurement.

According to one embodiment example, the sensor or a free end of thesensor unit projecting radially inwards is arranged at leastapproximately flush with an/the internal sleeve surface of the wall.Favorable flow conditions can be ensured as a result. Swirls caused byundercuts or edges can largely be prevented. This means that a risk ofblood clots or hemolysis can also be reduced.

The sensor can thereby be arranged in a radial position, which at leastapproximately corresponds to a radial distance of an internal sleevesurface of the line to the central longitudinal axis in the area of theradial cavity. In other words, the sensor can be arranged in a radialposition which is characterized by a radial distance to the centrallongitudinal axis corresponding to half the diameter, i.e., the radiusof the longitudinal cavity. The sensor can delimit the longitudinalcavity in a radial direction.

According to one embodiment example, the radial cavity is an opening—inparticular, a cylindrical bore with a uniform diameter. This ensures aparticularly simple construction. An opening can easily be introducedinto the wall at any time thereafter, and also in any position.Furthermore, the sensor can be positioned in the radial cavity fromoutside.

According to one embodiment example, an internal surface of the radialcavity is cylindrical or conical, or has a polygonal cross section. Atthe same time, the radial cavity is not necessarily round or circular,but can have any cross section. Where it has a round or circulargeometry, the radial cavity can be easily sealed—in particular, by meansof an oversize fit.

According to one embodiment example, a diameter or an extent of a crosssection of the radial cavity is smaller than a section of the sensorunit—in particular, of the sensor as well—that corresponds geometricallythereto. The individual interface can thus, to a large extent, be sealedindependently of any substance-to-substance connection. Asubstance-to-substance connection is not necessary in the area of theinternal surface of the radial cavity. At the same time, the radialcavity can, together with the sensor unit and/or the sensor, form anoversize fit to which the wall can be sealed fluid-tight. In otherwords, a corresponding geometry can ensure the fluid-tightness of theradial cavity between the sensor and the wall, even if no adhesiveagent, adhesive, or the like is provided for on this interface.

The radial cavity is preferably circular. This facilitates an exact-fitarrangement of the sensor unit in the radial cavity—in particular,independently of a specific rotation position.

An oversize fit thereby preferably means an interface at which one ofthe components to be coupled has a specific measurement through which itcan be ensured that the two components to be coupled can only beconnected to one another where they are geometrically aligned on top ofeach other, and that a gap-free connection, free of play, is ensured.

A diameter or an extent of a cross section of the radial cavity isthereby in the range, for example, of 1 mm to 5 mm—preferably in therange of 2 mm to 4 mm, more preferably in the range of 2.5 mm to 3.5 mm,and particularly in the range of 3 mm to 3.3 mm—especially 3.15 mm.According to a variant, the sensor unit then has a radial section whichhas a diameter or an extent in the range of 1 mm to 5 mm—preferably inthe range of 2 mm to 4 mm, more preferably in the range of 2.5 mm to 3.5mm, and particularly in the range of 3 mm to 3.3 mm—especially 3.1mm—wherein the radial section forms an oversize fit—in particular, apress fit—with an internal surface of the radial cavity. A sealing ofthe radial cavity can thus result—in particular, also without anyadhesive agent in the area of the radial cavity.

According to a special embodiment example, the wall has an at leastapproximately constant diameter and/or an at least approximatelyconstant wall thickness. It can thus be ensured that the sensor can bepositioned in a pre-definable radial position by means of the sensorunit, and, indeed, irrespective of which point on the wall the radialcavity is inserted at.

According to a special embodiment example, the sensor extends at leastapproximately across the entire cross section profile of the radialcavity and has at least approximately the same extent as a diameter oran extent of the radial cavity. The entire cross section of the radialcavity can thus be used for the measurement—in particular, the pressuremeasurement. In other words, the radial cavity can have a comparativelysmall design. In particular, the radial cavity can have a diameter whichis only as big as or only slightly larger than is required for themeasurement.

According to a special embodiment example, the sensor and/or the sensorunit has a front surface which is arranged radially flush to an internalsleeve surface of the line, wherein the front surface further forms thewall—in particular, across the entire cross section surface of theradial cavity. A transition between the internal sleeve surface and theradial cavity can thus be formed, so that undercuts or edges, and theswirls or dead spaces potentially concomitant therewith, can be avoidedto a great extent. Mention should also be made of the fact that thesensor does not extend into the line cross section. According to aspecial variant, the front surface is designed to correspondgeometrically to the geometry of the internal sleeve surface—inparticular, to be concavely curved. A shape-optimized integration canthus result. The sensor is thereby not at all “visible” for the bloodstream. A risk of swirls can be as good as ruled out.

According to one embodiment example, the sensor unit is configured toposition the sensor in a predefined radial position in the radialcavity—in particular, by the fact that the sensor unit is designed in asection configured for it geometrically corresponding to an externalsleeve surface of the line/wall. For this purpose, the sensor unit canbe designed, at least in sections, such that the sensor unit can bepositioned in a predetermined relative position directly on the wall.The radial position of the sensor can thus be predetermined bygeometrical configuration of the sensor unit. For example, the assemblyof the sensor in the “correct” position can thereby also be simplified.For example, the sensor unit need only be arranged on the externalsleeve surface—in particular, in a longitudinal alignment correspondingto the central longitudinal axis.

According to one embodiment example, the sensor unit has an abuttingsection which is designed to geometrically correspond to an/the externalsleeve surface of the wall in at least the area of the radial cavity—inparticular, circumferentially around the radial cavity. The sensor unitcan thus be easily and robustly connected to the line and can, inparticular, be affixed to the line in the area of the radial cavitycircumferentially around the radial cavity. The abutting section has,for example, a concave contour which is designed to geometricallycorrespond to a convex contour of the line or wall.

The abutting section is thereby preferably configured to define theradial position of the sensor—namely, via the external sleeve surface ofthe wall. In other words, a radial extension of a sensor mounting or ofa radial section of the sensor unit is adapted to the geometry of theabutting section such that, when the abutting section lies flat on theexternal sleeve surface of the wall, the sensor is arranged in apredetermined radial position—in particular, within the radial cavity.

An abutting section thereby preferably means a flat section on which thesensor unit can abut against the line. The abutting section is alsopreferably inherently stable, i.e., not elastically or plasticallydeformable, so that a relative movement between the line and theabutting section can be avoided in the area of the radial cavity. Thiscan ensure a permanent, reliable connection between these twocomponents.

In an advantageous embodiment of the invention, the sensor unit ispartially arranged in the radial cavity in the wall and integrated inthe wall such that the sensor is in communication with the fluid, andthe abutting section of the sensor unit is designed circumferentiallyaround the radial cavity and geometrically corresponds to an/theexternal sleeve surface of the wall.

The sensor unit, therefore, has a part, i.e., the sensor or at least apart of the sensor, which is located in the radial cavity in the wall ofthe line and another part which is arranged externally on the line andcan be moved across the flat section to abut against the external wallof the line. By means of the substance-to-substance connection of theflat section or of the abutting section of the sensor unit around thesensor in the radial cavity, an optimum sealing of the line is ensuredto the outside. Alongside the substance-to-substance fixation of thesensor unit to the line, by means of the protrusion of the sensor intothe radial cavity, a mechanical fixation—in particular, with regard totensile forces in the direction of the longitudinal extension of theline—is also ensured.

According to one embodiment example, the sensor unit has an abuttingsection which, at least in the area of the radial cavity—in particular,circumferentially around the radial cavity—is connectedsubstance-to-substance with an/the external sleeve surface of the lineor wall—in particular, by means of an adhesive agent. The sensor unitcan thus be affixed to the line in a robust way. Thesubstance-to-substance connection in the area of the external sleevesurface also has the advantage that any adhesive agent—in particular,glue—does not necessarily have to be provided on an internal surface ofthe radial cavity. It can thus be avoided that the fluid—especially,blood—comes into contact with the adhesive agent. The adhesive agent ispreferably flexible and moisture resistant. The adhesive agent ispreferably constituted so as to ensure a permanent adhesive connectionto plastic—especially, PVC. The adhesive agent is preferably a curingglue.

For example, the abutting section in the area of the radial cavity isconnected circumferentially around the radial cavity with the externalsleeve surface by means of the adhesive agent, wherein the sensor unitabuts exactly and fluid-tight directly against an internal surface ofthe radial cavity, without an adhesive agent. On the one hand, arelatively robust, durable flat connection is thereby ensured betweenthe line and the abutting section. On the other hand, it can beeffectively avoided that the line is twisted relative to the sensorunit.

It should be noted that an exclusive arrangement of the sensor and thesensor unit in the radial cavity of a flexible or elastic line can beproblematic, since leakages can easily occur if the flexible or elasticline moves or is moved, while the sensor, or the sensor unit, providedas a rigid component, is arranged rigidly in the radial cavity andcannot move in line with this movement. It could, therefore, result inleakages in the substance-to-substance connection of the sensor unit inthe cavity to the wall of the line.

According to one embodiment example, the sensor unit has a radialsection in which the sensor is arranged, wherein the radial cavitypreferably has an extension in a radial direction, which is preferablylarger than half of a wall thickness of the wall in a section in whichthe radial cavity is arranged. The sensor can thus be arranged by meansof the radial section in a predefined position in the radial cavity—inparticular, in a comparatively exact way in an exactly pre-definableradial position, e.g., exactly at the height of the internal sleevesurface of the wall. According to one variant, the radial extension cancorrespond at least approximately to the wall thickness, so that thesensor can be positioned almost in the flow path, i.e., almost at thesame radial distance from a central longitudinal axis of the line as theinternal sleeve surface of the wall. The radial section can thereby beadapted to the wall thickness. In other words, the position of thesensor can be set/defined by a predetermined radial extension of theradial section.

A radial section thereby preferably means a section extending in aradial direction which is configured to be coupled to the radial cavityand which is designed in cross section to geometrically correspond tothe cross-sectional profile of the radial cavity. The radial section canthereby comprise a sensor mounting which is configured to hold or affixthe sensor to the sensor unit. A sensor mounting thereby preferablymeans a part of the sensor unit on which the sensor (or a quite specifictype of sensor) can be positioned on the sensor unit, insofar as thesensor is not integrated in the sensor unit or formed by the sensorunit. The sensor mounting can thereby also have, for example, electricalcontacts by means of which the sensor is in electrical contact with acable or any communication interface or energy supply. The radialsection can thereby also be formed at least sectionally by the sensormounting.

According to one embodiment example, the sensor unit, at leastpartially—or at least a/the radial section of the sensor unit—isdesigned from a plastic material. An interface to the wall can thus beprovided which can also be effectively sealed—in particular, with PVChoses. An abutting section of the sensor unit can also thereby beeffectively connected to the wall (advantageous material pairing).

According to one embodiment example, the measuring device is adisposable device provided for one-time use, wherein the sensor unitpreferably has a coupling point for a communication and/or energysupply—in particular, for a transmission by wire over a cable or for awireless transmission. The integration of the sensor in the wallfacilitates a measuring device of simple design, in which, for example,only a cable or a stick must be removed before the measuring device isdisposed of.

According to one embodiment example, a measuring system forextra-corporeal circulation with at least two measuring devicesaccording to the invention can be created, wherein one of the measuringdevices has a feed line and another of the measuring devices has adischarge line. In this way, a property—in particular, a pressure of adischarged fluid, as well as of a fed fluid—in a circulation can bemeasured. In so doing, in the discharge line in particular, the risk(especially, on any Luer connections) that air be drawn into the line,can be reduced. In the discharge line, the risk, in particular, that(especially on any Luer connections) the fluid (in particular, blood) bepressed out or spurt out in the event of an over pressure, can bereduced. In other words, the integration of the sensors in the wall hasthe advantage that leakages can largely be ruled out. The number ofinterfaces can be reduced—in particular, to a single interface per line.

The aim is also accomplished by a method for producing amedico-technical measuring device—in particular, a medico-technicalmeasuring device according to the invention—comprising the steps:

-   -   providing a line with a wall—in particular, a flexible, pliable        hose line;    -   arranging a sensor in the line;

for which it is envisaged according to the invention that a radialcavity be inserted in the wall in a radial direction and the sensor bearranged in the radial cavity—in particular, in a radial positionbetween an external sleeve surface and an internal sleeve surface of thewall at a distance from the external sleeve surface. Thus result, inparticular, the advantages explained in connection with the measuringdevice.

According to one embodiment example of the method, the measuring deviceis connected substance-to-substance with an external sleeve surface ofthe wall, and/or the sensor in the radial cavity is positionedfluid-tight in an oversize fit in the wall. A measuring device can thusbe provided which has a single, comparatively robust, and durableinterface which can be sealed fluid-tight with good reliability. Theseal preferably takes place in the radial cavity alone, and thedistinct, relative position can preferably be ensured by thesubstance-to-substance connection. A substance-to-substance connectioncan thereby increase the robustness.

The aim is also accomplished by a method for measuring by means of amedico-technical measuring device—in particular, for pressuremeasurement by means of a medico-technical measuring device according tothe invention—comprising the steps:

-   -   guiding a fluid—in particular, blood—through a line within a        longitudinal cavity delimited by a wall—in particular, through a        hose line;    -   measuring a property of a fluid by means of a sensor of the        measuring device;

for which it is envisaged according to the invention that the sensor bepositioned in a radial cavity inserted in the wall, and the property bemeasured in the radial cavity—in particular, in a radial positionbetween an external sleeve surface and an internal sleeve surface of thewall at a distance from the external sleeve surface. The measurement—inparticular, pressure measurement—can ensue “inline” within the wall. Theintegrated arrangement of the sensors permits an “inline” measurementwithout a time lag.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspectival view in a schematic representation of a line ofa medico-technical measuring device according to one embodiment exampleof the invention;

FIG. 2 is a perspectival view in a schematic representation of a sensorunit of a medico-technical measuring device according to one embodimentexample of the invention in an arrangement on the line shown in FIG. 1;

FIG. 3 is a side view in a schematic representation of amedico-technical measuring device according to one embodiment example ofthe example;

FIGS. 4 and 5 are different perspectival sliced views in a schematicrepresentation of the medico-technical measuring device shown in FIG. 3;and

FIG. 6 is a side view in a schematic representation of a sensor unit ofa medico-technical measuring device according to one embodiment exampleof the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

In connection with the description of the following figures, referenceis made to the embodiment example in FIG. 1 for reference signs whichare not explicitly explained.

FIG. 1 shows a line 20 in the form of a hose line which has a wall 22.The line 20 can be designed from an elastic material and be flexible orpliable. The wall 22 has an external sleeve surface 22.1 and an internalsleeve surface 22.2. The wall 22 or the internal sleeve surface 22.2delimits a longitudinal cavity 24, in which a fluid—in particular,blood—can be guided. The line 20 extends in a longitudinal directionalong a central longitudinal axis M. A radial cavity 26 is inserted inthe wall 22 in a radial direction r. The radial cavity 26 is a radialopening in the form of a hole, which extends from the external sleevesurface 22.1 to the internal sleeve surface 22.2 and forms a passage. Asensor or a sensor unit can now be positioned in this passage, and aseal can thereby ensue by means of the sensor or the sensor unit, as isexplained in connection with the following figures.

FIG. 2 shows a medico-technical measuring device 10 which has the line20 and a sensor unit 30 described in FIG. 1. A sensor 32 is arranged inor on the sensor unit 30. The sensor 32 can be interpreted as acomponent of the sensor unit 30. The sensor 32, or, at least partially,the sensor unit 30 also, is arranged in the radial cavity 26, whereinthe sensor 32 is positioned between the external sleeve surface 22.1 andthe internal sleeve surface 22.2. The sensor unit 30 has a radialsection 36 extending in a radial direction and an abutting section 38extending in a longitudinal direction. The radial section 36 comprises asensor mounting 34, in which the sensor 32 is arranged. The sensormounting 34 and/or the sensor 32 are designed to geometricallycorrespond to the radial cavity 26. The abutting section 38 abutsagainst the external sleeve surface 22.1—in particular, flatcircumferentially around the radial cavity 26.

FIG. 3 shows a medico-technical measuring system 1, which comprisesinter alia the medico-technical measuring device 10 depicted in FIG. 2,as well as an extrusion 9 with a passage 9.1, wherein the sensor 32 isin communication with the environment U via the passage 9.1. The sensor32 is covered by a cover 14 and protected by an air-permeable,water-repellent membrane 16. FIG. 3 shows in detail that the radialsection 36 abuts in an exactly flat manner against an internal surface26.1 of the radial cavity 26—in particular, circumferentially—in orderto be able to ensure a sealing of the longitudinal cavity. However, theabutting section 38 contacts only the external sleeve surface 22.1 and,in fact, in sections—directly and/or, optionally (as indicated),indirectly via an adhesive agent 12. The adhesive agent 12 is preferablyprovided completely circumferentially around the radial cavity 26 on theexternal sleeve surface 22.1 and/or the abutting section. However, theadhesive agent 12 is not provided on the internal surface 26.1—inparticular, to be able to avoid contact with the fluid guided in thelongitudinal cavity.

The radial position of the sensor 32 explained by means of FIG. 3 isgiven only as an example. The radial position of the sensor 32 candeviate from the position shown. In particular, the sensor 32 can bearranged further inside closer to the internal sleeve surface 22.2,which can provide advantages in many applications, e.g., advantages of adirect “inline” measurement in the flow path, i.e., at least almostwithout the influence of any flow swirls on any undercuts or edges.

The wall 22 has a wall thickness r22, which is, for example, in therange of 1 mm to 5 mm—in particular, in the range of 1.6 mm to 2.4 mm.The radial position of the sensor 32 is at least approximately centralin relation to the external and internal sleeve surfaces 22.1, 22.2. Theradial section 36 can, however, have a larger radial extension thanshown. In particular, the radial section 36 can have a radial extensionwhich is in the range of the wall thickness r22.

FIGS. 4 and 5 show further components of the measurement system 1—inparticular, a female plug 5—which provides a coupling point for acommunication and/or energy supply, and a button 7 for manual operationof the measurement system 1. The female plug 5 is connected to thesensor unit 30 and the sensor 32 by means of an adapter cable 3, whichis arranged in the extrusion 9.

The female plug 5 shown in FIG. 5 is configured to accommodate either aplug in conjunction with an (external) cable or a type of “stick” ormodule. The stick can ensure wireless communication, e.g., via WLAN,radio, or Bluetooth. The stick can also have an energy supply, e.g., abattery. The female plug 5 can thereby have the same form for bothvariants, so that a user can decide in each case whether a wired energysupply and communication is required, or whether the communicationshould be effected wirelessly and the energy supply provided via thestick, e.g., by means of batteries integrated in the stick. Both thecable and the stick can thereby be used multiple times. In other words,the medico-technical measuring system 1 or the medico-technicalmeasuring device 10 can be provided for one-time use (“disposable”),and, prior to disposal, the cable or the stick can be uncoupled from thefemale plug.

FIG. 6 shows a medico-technical measuring device 10 which is assembledcomparably to the sensor unit 30 shown in FIG. 2. With this sensor unit30, the extension of the radial section 36 is adjusted to the wallthickness of the wall 22, such that the sensor 32 is arranged flush withthe internal sleeve surface 22.2.

LIST OF REFERENCE SYMBOLS

-   -   1 Medico-technical measuring system—in particular, pressure        measurement system    -   3 Adapter cable    -   5 Female plug    -   7 Button    -   9 Extrusion    -   9.1 Passage in extrusion    -   10 Medico-technical measuring device    -   12 Adhesive agent—in particular, glue    -   14 Cover—in particular, protective cap    -   16 Membrane    -   20 Line—in particular, hose line    -   22 Wall    -   22.1 External sleeve surface of the wall    -   22.2 Internal sleeve surface of the wall    -   24 Longitudinal cavity    -   26 Radial cavity—in particular, radial opening    -   26.1 Internal sleeve surface of the radial cavity    -   30 Sensor unit—in particular, pressure sensor unit    -   32 Sensor—in particular, pressure sensor    -   34 Sensor mounting    -   36 Radial section    -   38 Abutting section    -   M Central longitudinal axis    -   r Radial direction    -   r22 Wall thickness of the wall

1.-16. (canceled)
 17. A medico-technical measuring device for measuringa property of a fluid, comprising: a line which extends along a centrallongitudinal axis and is configured to guide a fluid within alongitudinal cavity delimited by a wall; and a sensor unit with asensor, configured to measure a property of the fluid guided in thelongitudinal cavity; wherein the line has a radial cavity defined in thewall in a radial direction, and wherein the sensor unit is at leastpartially arranged in the radial cavity and is integrated in the wall,such that the sensor is in communication with the fluid.
 18. A measuringdevice according to claim 17, wherein the measuring device is configuredto connect the sensor unit in a single interface with the line.
 19. Ameasuring device according to claim 17, wherein the measuring device isconfigured to attach the sensor unit directly to an external sleevesurface of the wall.
 20. A measuring device according to claim 17,wherein the wall of the line has an external sleeve surface and aninternal sleeve surface, the sensor being arranged in a radial positionbetween the external sleeve surface and the internal sleeve surface ofthe wall inside the wall and spaced from the external sleeve surface.21. A measuring device according to claim 20, wherein the sensor isdisposed closer to the internal sleeve surface than to the externalsleeve surface.
 22. A measuring device according to claim 17, whereinthe radial cavity is an opening.
 23. A measuring device according toclaim 22, wherein the opening is a cylindrical bore with a uniformdiameter.
 24. A measuring device according to claim 17, wherein adiameter or an extent of a cross section of the radial cavity is smallerthan a section of the sensor unit that corresponds geometricallythereto, wherein the radial cavity, together with the sensor unit and/orthe sensor, forms an oversize fit to which the wall can be sealed in afluid-tight manner.
 25. A measuring device according to claim 17,wherein the sensor unit is configured to position the sensor in apredefined radial position in the radial cavity.
 26. A measuring deviceaccording to claim 17, wherein the sensor unit has an abutting sectionthat geometrically corresponds to an external sleeve surface of thewall, at least in the area of the radial cavity.
 27. A measuring deviceaccording to claim 26, wherein the abutting section geometricallycorresponds circumferentially around the radial cavity.
 28. A measuringdevice according to claim 27, wherein the sensor unit is partiallyarranged in the radial cavity in the wall and integrated in the wallsuch that the sensor is in communication with the fluid and such thatthe abutting section of the sensor unit lies circumferentially aroundthe radial cavity and to geometrically correspond to the external sleevesurface of the wall.
 29. A measuring device according to claim 27,wherein the abutting section of the sensor unit in the area of theradial cavity and circumferentially around the radial cavity isconnected substance-to-substance with the external sleeve surface of thewall.
 30. A measuring device according to claim 29, wherein thesubstance-to-substance connection is by means of an adhesive agent. 31.A measuring device according to claim 17, wherein the sensor unit has aradial section in which the sensor is arranged, wherein the radialsection has an extension in a radial direction, the extension beinglarger than half of a wall thickness of the wall of the line in asection in which the radial cavity is arranged.
 32. A measuring deviceaccording to claim 31, wherein the radial section of the sensor unit isformed from a plastic material.
 33. A measuring device according toclaim 17, wherein the sensor unit is formed from a plastic material. 34.A measuring device according to claim 17, wherein the measuring deviceis a disposable device provided for one-time use.
 35. A measuring deviceaccording to claim 34, wherein the sensor unit has a coupling point fora communication and/or energy supply
 36. A measuring device according toclaim 35, wherein the communication is for a transmission by wire over acable or for a wireless transmission.
 37. A measuring system forextra-corporeal circulation with at least two measuring devicesaccording to claim 17, wherein one of the measuring devices has a feedline, and the other of the measuring devices has a discharge line.
 38. Ameasuring system according to claim 17, wherein the fluid is blood. 39.A measuring system according to claim 17, wherein the property of thefluid is pressure.
 40. A medico-technical measuring device for measuringa property of a fluid, comprising: a line which extends along a centrallongitudinal axis and is configured to guide a fluid within alongitudinal cavity delimited by a wall; and a sensor unit with asensor, configured to measure a property of the fluid guided in thelongitudinal cavity; wherein the line has a radial cavity defined in thewall in a radial direction, and wherein the sensor unit is at leastpartially arranged in the radial cavity and is integrated in the wall,such that the sensor is in communication with the fluid, the sensorhaving a surface positioned within the wall.
 41. A method for producinga medico-technical measuring device according to claim 17, comprisingthe steps of: providing a flexible and pliable hose line with a wall;arranging a sensor in the line; wherein a radial cavity is inserted inthe wall in a radial direction, and the sensor is arranged in the radialcavity.
 42. A method according to claim 41, wherein the sensor isarranged in a radial position between an external sleeve surface and aninternal sleeve surface of the wall.
 43. A method according to claim 42,wherein the measuring device is connected substance-to-substance with anexternal sleeve surface of the wall, and/or the sensor in the radialcavity is positioned fluid-tight in the wall.
 44. A method for measuringa property of a fluid by means of a medico-technical measuring deviceaccording to claim 17, comprising the steps of: guiding a fluid througha line within a longitudinal cavity delimited by a wall; measuring aproperty by means of a sensor of the measuring device; wherein that theproperty is measured in a radial cavity inserted in the wall in whichthe sensor is positioned.
 45. A method according to claim 44, whereinthe sensor is positioned in a radial position between an external sleevesurface and an internal sleeve surface of the wall distanced from theexternal sleeve surface.
 46. A method according to claim 45, wherein thesensor is positioned in a radial position closer to the internal sleevesurface than to the external sleeve surface.